Trap levels in layered semiconductor Ga2SeS

Trap levels in nominally undoped Ga2SeS layered crystals have been characterized by thermally stimulated current (TSC) measurements. During the measurements, current was allowed to flow along the c-axis of the crystals in the temperature range of 10–300 K. Two distinct TSC peaks were observed in the spectra, deconvolution of which yielded three peaks. The results are analyzed by curve fitting, peak shape and initial rise methods. They all seem to be in good agreement with each other. The activation energies of three trapping centers in Ga2SeS are found to be 72, 100 and 150 meV. The capture cross section of these traps are 6.7×10−23, 1.8×10−23 and 2.8×10−22 cm2 with concentrations of 1.3×1012, 5.4×1012 and 4.2×1012 cm−3, respectively.